The present invention relates to an electronic watch with a chronograph system having an analog time-display.
In a conventional analog watch with a chronograph system, a resetting mechanism is provided for each chronograph device, such as the hour-hand shaft, minute-hand shaft, and second-hand shaft. The resetting mechanism comprises a heartcam secured to a corresponding shaft, a hammer adapted to be engaged with the heart to rotate the hand on the shaft to the zero position, and a slipping mechanism for allowing the shaft to rotate to the zero position. Such a mechanism renders the construction of the chronograph system complicated and thick. In order to simplify the construction and to reduce the thickness, a motor is provided for each chronograph device. Each motor is adapted to be electrically controlled so as to be started, stopped, and reset to the zero position.
However, such a system causes the cost of the watch to rise. In addition, each hand must be reset to the zero position by operation of its respective motor. It is desirable to quickly return each hand to the zero position. However, it takes a long time to reset the minute hand and hour hand to zero positions by motors which are operated pulses, because the motors for watches can not be operated by at very high speed. In order to rotate the minute hand at a high speed, it is proposed to rotate the hand one step for each one (minute) pulse. By such a driving system, although the minute hand is reset at a high speed by high frequency pulses, it is difficult to exactly stop the minute hand at a desired position by such a large step driving in the chronograph time mode. More particularly, if the hand stops at a position deviated from an index, which is caused, for example, by eccentric disposition of wheels by error, the user might misread the chronograph time.